Oh I wouldn’t say he abdicated because of the tiring tea parties. The emperor and the empress are often seen visiting all sorts of places around the country to show support. The most prominent example would be attending the earthquake-stricken areas and talking to the people in shelters. That's what the prime minister is also expected to do, but is often postponed or cancelled. I'd say that the emperor is taking his role seriously and that might be the reason he has to slow down and only reduce his involvement to the aforementioned tea parties. The emperor has also shown discomfort with the path Abe is taking the country.